honestly, the last thing I would do is leave this issue in the hands of an endocrinologist..
all they're going to do is bumrush your system with hormone or anti-hormone related drugs
trust me man, surgery is the ONLY way, the sooner u begin to accept that, the better off you'll be.
He needs to keep seeing his endo, I really hope he doesnt follow ur advice. Do u realise the gyno is cosmetic? so he gets surgery gets it cut off and then what? he is still hypogonadal has aching joints and high estrogen